Provide ability to override url username and password
Provide ability to override url username and password

This is modeled after the govc behavior and is needed when the username and/or password contain special characters that makes it unable to specify them in an URL.

gonkulator/govmomi,logankimmel/govmomi,jrmycanady/govmomi,chrislovecnm/govmomi,egorovv/govmomi,abathla/govmomi,ilikejam/govmomi,higebu/govmomi,daxgames/govmomi,vmware/govmomi,austinlparker/govmomi,chrislovecnm/govmomi,casualjim/govmomi,excilsploft/govmomi,runner-mei/govmomi,gonkulator/govmomi,kristinn/govmomi,casualjim/govmomi,austinlparker/govmomi,frapposelli/govmomi,cgtexmex/govmomi,excilsploft/govmomi,frapposelli/govmomi,gonkulator/govmomi,caglar10ur/govmomi,l1jiang/govmomi,dougm/govmomi,higebu/govmomi,mevansam/vsphere-govmomi,daxgames/govmomi,bruceadowns/govmomi,l1jiang/govmomi,excilsploft/govmomi,vmware/govmomi,mevansam/vsphere-govmomi,cgtexmex/govmomi,logankimmel/govmomi,logankimmel/govmomi,ilikejam/govmomi,kristinn/govmomi,l1jiang/govmomi,runner-mei/govmomi,cgtexmex/govmomi,RotatingFans/govmomi,daxgames/govmomi,kristinn/govmomi,higebu/govmomi,chrislovecnm/govmomi,jrmycanady/govmomi,vmware/govmomi,RotatingFans/govmomi,dougm/govmomi,austinlparker/govmomi,bruceadowns/govmomi,casualjim/govmomi,egorovv/govmomi,ilikejam/govmomi,egorovv/govmomi,runner-mei/govmomi,caglar10ur/govmomi,frapposelli/govmomi,RotatingFans/govmomi,bruceadowns/govmomi,abathla/govmomi,abathla/govmomi,caglar10ur/govmomi,mevansam/vsphere-govmomi,dougm/govmomi,jrmycanady/govmomi